I was mudding my vaterra Halix in the swamp. It has some of that grassy shit that wraps around your tire and forces your motor from moving. When I was done I rode it in my yard for a good 2 minutes until I went up a hill and only the front tires were moving. Also the rear left axle was moving but not the tire, and the rear right tire and axle weren't moving at all. I have a metal spur gear which I was warned could strip the diff!
If anybody knows what is wrong please help me! Thank you Aedan...

Time to take it apart to check it out. Use the exploded view in the manual to get it apart. You may have something jammed in the axles or it could have stripped something.

The axle was rotating but not the tire..did you strip out or break something that connects the wheels to the axle? Try spinning your back wheels while in the air "with out a load"if one tire spins and the other tire stays still.then it.s probably not your diff..

Thank you for what you said I found out the the little pin that hold the axle in must have fell off causing the diff to not engage or something weird like that on the other side. It all works now good thing I always have extra parts!

Most excellent!

Every time you take it apart you will learn something new.

If you have a semi popular car, search youtube. There are many videos on how to maintain and upgrade specific parts.

And yes, you can NEVER have too many spares. lol